The inscription on the ash try reads. Made from Ex German submarine DEUTSCHLAND broken up by ROBERT SMITH & SONS BIRKENHEAD. The submarine was surrended in 1918 as part of the armistice and was on exhibition in London. It was sold for scrap in 1921. When being broken up by Robert Smith & sons an explosion ripped the ship apart killing 5 apprentices. More info on Wikipedia.

Das Boot was the nearest depiction I've seen to submarine life as it really is but even then, after watching it several times there are chinks in the technical armour, which tends to spoil it a bit for actual submariners but it is nonetheless a cracking film. I drew the line at my kids feeling sorry for the crew when they were being snottered at the end though, I had to give them a mini History lesson that they were the baddies.